Set - 2

What is the purpose of the following files having extensions: frm, myd, and myi? What these files contain?

Answer :

In MySQL, the default table type is MyISAM.
Each MyISAM table is stored on disk in three files. The files have names that begin with the table name and have an extension to indicate the file type.

The '.frm' file stores the table definition.
The data file has a '.MYD' (MYData) extension.
The index file has a '.MYI' (MYIndex) extension

Question 13 :

If the variable $a is equal to 5 and variable $b is equal to character a, what's the value of $$b?

Answer :

100, it's a reference to existing variable.

Question 14 :

How To Protect Special Characters in Query String?
If you want to include special characters like spaces in the query string, you need to protect them by applying the urlencode() translation function. The script below shows how to use urlencode():